Amiga.org

Amiga computer related discussion => Amiga Hardware Issues and discussion => Topic started by: Effy on January 27, 2004, 10:32:42 PM

Title: What ´s the difference between a normal EDO mudule and a more expensive "+ parity"
Post by: Effy on January 27, 2004, 10:32:42 PM

Here is the Dutch link (http://cgi.benl.ebay.be/ws/eBayISAPI.dll?ViewItem&category=1482&item=3453610388) , with a link to an english site of White Lake. The question is what that extra parity means ?! Why is is more expensive than a similar module of the same manufacturer without parity ??? Can we use it in turbocards ?? Has it got any advantages or not to us Amiga freaks ???

Title: Re: What ´s the difference between a normal EDO mudule and a more expensive "+ p
Post by: redrumloa on January 27, 2004, 10:55:42 PM

AFAIK no Amiga turbo card ever made takes advantage of parity memory. The card may be able to use it, but with no extra benefit.

In simple terms, nonparity SIMMS are 32bit and parity simms are 36 bit. The extra 4bit are error correction, but amiga accelerators simply ignore the extra 4 bits.

Title: Re: What ´s the difference between a normal EDO mudule and a more expensive "+ p
Post by: terminator on January 27, 2004, 11:09:46 PM

Quote

The question is what that extra parity means ?! Why is is more expensive than a similar module of the same manufacturer without parity ??? Can we use it in turbocards ?? Has it got any advantages or not to us Amiga freaks ???

Parity RAM was used on the old PC systems.  they needed an extra bit, to check for errors.  So an extra IC would be installed to provide a place to store the parity bits.

You could use the parity RAM SIMMS on an Amiga, the card's memory subsystem just ignored the extra bit.  It was only looking for 8 bits, not nine.javascript:%20justReturn()

I argued with a PC dealer that to make 2M of RAM on a SupraRAM card I only needed 16 DIPs, not 18.  I had to have parity, he insisted... javascript:%20justReturn()

Title: Re: What ´s the difference between a normal EDO mudule and a more expensive "+ p
Post by: JetRacer on January 27, 2004, 11:36:42 PM

You can find memory with and without EDO too. Amiga's can take advantage of EDO, but not parity.

Title: Re: What ´s the difference between a normal EDO mudule and a more expensive "+ p
Post by: odin on January 27, 2004, 11:41:06 PM

To be exact only some turboboards can exploit the EDO characteristic. AFAIK.

Title: Re: What ´s the difference between a normal EDO mudule and a more expensive "+ p
Post by: PiR on January 28, 2004, 04:32:15 PM

Yep, and the most can show trouble using them. AFAIK.

Title: Re: What ´s the difference between a normal EDO mudule and a more expensive "+ p
Post by: odin on January 28, 2004, 04:40:08 PM

Don't know really.....I thought most cards had no problem with EDO.